A starch carbon aerogel adsorbent, its preparation method and application

Abstract

The application provides a starch carbon aerogel adsorbent and a preparation method and application thereof, and belongs to the technical field of printing and dyeing wastewater treatment. Starch is mixed with water to obtain gelatinized starch; the gelatinized starch, sodium carboxymethyl cellulose, grafting monomers, an initiator and a crosslinking agent are mixed to perform grafting and crosslinking reactions to obtain a starch-based hydrogel; the grafting monomers include acrylamide, acrylic acid and 2-acrylamide-2-methylpropanesulfonic acid, and the crosslinking agent includes N,N-methylenebisacrylamide; the starch-based hydrogel is sequentially subjected to freeze drying and calcination to obtain the starch carbon aerogel adsorbent. Nitrogen and sulfur atoms are introduced into the hydrogel through crosslinking and grafting reactions, and the carbon aerogel with uniform distribution of nitrogen and sulfur atoms is obtained after calcination. The hydrogel has a three-dimensional structure, and the structure is retained after calcination, so that the carbon aerogel has a high specific surface area.

Description

Technical Field

[0001] This invention relates to the field of dyeing and printing wastewater treatment technology, and in particular to a starch-carbon aerogel adsorbent, its preparation method, and its application. Background Technology

[0002] Typically, carbon aerogels are prepared from resorcinol and formaldehyde via sol-gel polymerization, supercritical drying, and high-temperature carbonization in an aqueous solution. However, formaldehyde is highly toxic and poses a significant health risk, resorcinol is expensive, and the traditional preparation cycle for carbon aerogels is long. These factors severely limit the commercial application of carbon aerogels. To address these issues, biomass carbon aerogels have been gradually developed. The biomass used to prepare carbon aerogels is primarily cellulose, which possesses a certain three-dimensional structure and retains its integrity after calcination. Cellulose carbon aerogels are mainly prepared by shaping cellulose and using acid-base separation to elute cellulose and impurities. The final cellulose carbon aerogel often requires KOH heat treatment for activation and pore structure adjustment, and it is primarily used as an electrode material.

[0003] There are few reports on the preparation of carbon aerogels using starch as a carbon source, mainly because starch does not have a fixed three-dimensional structure and its molecules do not contain heteroatoms other than C, H, and O. The carbon powder obtained by directly carbonizing starch, after activation, has a specific surface area of ​​only 100 m². 2 The surface area is around 1 / g, which presents a problem of small specific surface area. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a starch-carbon aerogel adsorbent, its preparation method, and its application. The starch-carbon aerogel adsorbent prepared by this invention can achieve a high specific surface area and adsorption capacity without activation.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] This invention provides a method for preparing a starch-carbon aerogel adsorbent, comprising the following steps:

[0007] Starch is mixed with water and gelatinized to obtain gelatinized starch;

[0008] The gelatinized starch, sodium carboxymethyl cellulose, grafting monomers, initiators and crosslinking agents are mixed and grafted and crosslinked to obtain a starch-based hydrogel; the grafting monomers include acrylamide, acrylic acid and 2-acrylamide-2-methylpropanesulfonic acid, and the crosslinking agent includes N,N-methylenebisacrylamide.

[0009] The starch-based hydrogel was subjected to freeze-drying and calcination in sequence to obtain the starch-carbon aerogel adsorbent.

[0010] Preferably, the mass ratio of sodium carboxymethyl cellulose to 2-acrylamide-2-methylpropanesulfonic acid is 0.5-1:0.5-2.

[0011] Preferably, the mass ratio of starch to sodium carboxymethyl cellulose is 1-2:0.5-1.

[0012] Preferably, the ratio of acrylamide, acrylic acid, and 2-acrylamide-2-methylpropanesulfonic acid is 2-3g:0-5mL:0.5-2g, and the amount of acrylic acid is not 0.

[0013] Preferably, the grafting and cross-linking reaction includes the following steps: heating from 60°C to 65-75°C and then holding at that temperature for 4-5 hours.

[0014] Preferably, the heating rate is 2.5°C / min.

[0015] Preferably, the freeze-drying temperature is -30 to -40°C.

[0016] Preferably, the calcination temperature is 700–900°C, the holding time is 2–3 hours, and the heating rate from room temperature to the calcination temperature is 2–5°C / min.

[0017] The present invention also provides a starch-carbon aerogel adsorbent prepared by the preparation method described in the above technical solution.

[0018] This invention also provides the application of the starch-carbon aerogel adsorbent described in the above technical solution in the field of organic dye adsorption.

[0019] This invention provides a method for preparing a starch-carbon aerogel adsorbent, comprising the following steps: mixing starch with water and gelatinizing it to obtain gelatinized starch; mixing the gelatinized starch, sodium carboxymethyl cellulose, grafting monomers, initiators, and crosslinking agents, and performing grafting and crosslinking reactions to obtain a starch-based hydrogel; wherein the grafting monomers include acrylamide, acrylic acid, and 2-acrylamide-2-methylpropanesulfonic acid, and the crosslinking agent includes N,N-methylenebisacrylamide; and sequentially freeze-drying and calcining the starch-based hydrogel to obtain the starch-carbon aerogel adsorbent.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] This invention provides a carbon aerogel adsorbent, which is obtained by freeze-drying and calcining starch as a raw material and starch-based hydrogel as a precursor. The starch-based hydrogel as the precursor is synthesized by grafting and cross-linking reactions in the presence of an initiator using corn starch and sodium carboxymethyl cellulose as raw materials, acrylamide (AM), acrylic acid (AA) and 2-acrylamide-2-methylpropanesulfonic acid (AMPS) as graft monomers, and N,N-methylenebisacrylamide (NMBA) as a cross-linking agent. Nitrogen and sulfur atoms are introduced into the hydrogel. The starch-based hydrogel is first freeze-dried and then calcined to obtain the starch carbon aerogel adsorbent with uniformly distributed nitrogen and sulfur atoms. In this invention, the starch-based hydrogel has a three-dimensional structure. After freeze-drying, a small number of pores are generated. After calcination, the three-dimensional structure of the starch-based hydrogel is preserved, so that the starch-carbon aerogel adsorbent can have a high specific surface area without strong alkali activation. Moreover, the starch-carbon aerogel adsorbent contains heteroatoms such as nitrogen and sulfur, which have a good adsorption effect on dyes, such as methylene blue. Its adsorption capacity can reach 960 mg / g, which is much larger than that of ordinary activated carbon (140 mg / g).

[0022] Furthermore, the raw material used in this invention is starch, which is inexpensive, clean, and non-toxic; the preparation process of starch-based hydrogels is simple, and no toxic gases are emitted during the calcination process. Attached Figure Description

[0023] Figure 1 The infrared spectrum of the starch-based hydrogel in Example 1;

[0024] Figure 2 The infrared spectrum of the starch-carbon aerogel adsorbent in Example 1;

[0025] Figure 3 Here is an electron microscope image of starch from Example 1;

[0026] Figure 4 Here is an electron microscope image of sodium carboxymethyl cellulose from Example 1;

[0027] Figure 5 Here is an electron microscope image of the starch-based hydrogel in Example 1;

[0028] Figure 6 This is an electron microscope image of the starch-carbon aerogel adsorbent in Example 1;

[0029] Figure 7 This is a photograph of the starch-based hydrogel in Example 1;

[0030] Figure 8 This is a photograph of the starch-based hydrogel after it has absorbed water, as shown in Example 1.

[0031] Figure 9This is a photograph of the starch-based hydrogel after freeze-drying in Example 1;

[0032] Figure 10 This is a photograph of the starch-carbon aerogel adsorbent used in Example 1. Detailed Implementation

[0033] This invention provides a method for preparing a starch-carbon aerogel adsorbent, comprising the following steps:

[0034] Starch is mixed with water and gelatinized to obtain gelatinized starch;

[0035] The gelatinized starch, sodium carboxymethyl cellulose, grafting monomers, initiators and crosslinking agents are mixed and grafted and crosslinked to obtain a starch-based hydrogel; the grafting monomers include acrylamide, acrylic acid and 2-acrylamide-2-methylpropanesulfonic acid, and the crosslinking agent includes N,N-methylenebisacrylamide.

[0036] The starch-based hydrogel was subjected to freeze-drying and calcination in sequence to obtain the starch-carbon aerogel adsorbent.

[0037] Unless otherwise specified, all raw materials used in this invention are commercially available products in the field.

[0038] This invention involves mixing starch with water and gelatinizing the mixture to obtain gelatinized starch.

[0039] In this invention, the starch is preferably corn starch.

[0040] In this invention, the preferred mass ratio of starch to water is 1 to 2:15.

[0041] In this invention, the gelatinization temperature is preferably 85-90°C, and the gelatinization time is preferably 15 min.

[0042] In this invention, the starch and water are stirred evenly and then placed in a water bath for gelatinization. After gelatinization is completed, the starch is preferably removed and cooled to room temperature for later use to obtain the gelatinized starch.

[0043] After obtaining gelatinized starch, the present invention mixes the gelatinized starch, sodium carboxymethyl cellulose, grafting monomer, initiator and crosslinking agent, and performs grafting and crosslinking reactions to obtain starch-based hydrogel; the grafting monomer includes acrylamide, acrylic acid and 2-acrylamide-2-methylpropanesulfonic acid, and the crosslinking agent includes N,N-methylenebisacrylamide.

[0044] In this invention, the initiator is preferably ammonium persulfate (APS).

[0045] In this invention, the preferred mass ratio of N,N-methylenebisacrylamide to ammonium persulfate is 0.1-0.2:0.05-0.06.

[0046] In this invention, the preferred mass ratio of sodium carboxymethyl cellulose to 2-acrylamide-2-methylpropanesulfonic acid is 0.5-1:0.5-2.

[0047] In this invention, the preferred mass ratio of starch to sodium carboxymethyl cellulose is 1-2:0.5-1.

[0048] In this invention, the preferred ratio of acrylamide, acrylic acid, and 2-acrylamide-2-methylpropanesulfonic acid is 2-3g:0-5mL:0.5-2g, and the amount of acrylic acid is not 0, more preferably 3g:5mL:2g.

[0049] In this invention, the sodium carboxymethyl cellulose and acrylic acid increase the number of carboxylic acid groups in the hydrogel. Carboxylic acid groups are hydrophilic groups that can increase the water absorption capacity of the starch-based hydrogel. By absorbing water and drying, more pores are created, increasing the specific surface area of ​​the starch carbon aerogel adsorbent. The acrylamide provides nitrogen heteroatoms, and the 2-acrylamide-2-methylpropanesulfonic acid provides sulfur heteroatoms.

[0050] In this invention, the acrylic acid is preferably neutralized by an inorganic alkaline substance before use, and the inorganic alkaline substance is preferably a sodium hydroxide solution.

[0051] In this invention, the mass fraction of the sodium hydroxide solution is preferably 15%.

[0052] In this invention, the neutralization is preferably performed to achieve a degree of neutralization of 60-80% for acrylic acid. If the degree of neutralization of the reaction system is low, the -COOH content is high, and adjacent -COOH groups easily form hydrogen bonds and undergo self-crosslinking reactions. Excessive crosslinking density results in a small volume of the formed three-dimensional network structure and low water absorption. As the degree of neutralization increases, the negatively charged -COOH groups... - The increase in the number of functional groups leads to increased electrostatic repulsion, causing the three-dimensional network structure to expand, which is beneficial to improving water absorption performance.

[0053] In this invention, the grafting and crosslinking reaction preferably includes the following steps: heating from 60°C to 65-75°C and then holding at that temperature for 4-5 hours. In this invention, the ammonium persulfate cannot generate free radicals below 60°C, and the grafting reaction cannot proceed. At 60°C, the raw materials are mixed uniformly, and as the temperature slowly increases, free radicals are generated. The grafting reaction proceeds under relatively mild conditions with good heat dissipation. If the grafting and crosslinking reaction is carried out directly at 65-75°C, the free radical reaction occurs violently, releasing a large amount of heat, which can easily lead to a sudden increase in the volume of the protective gas. Furthermore, the heat inside the starch-based hydrogel is difficult to dissipate, and explosive delamination may also occur.

[0054] In this invention, the heating rate is preferably 2.5°C / min.

[0055] In a specific embodiment of the present invention, preferably, deionized water is added to the sodium carboxymethyl cellulose and stirred until the powder is completely dissolved to obtain a transparent viscous substance; the acrylic acid is added dropwise to a sodium hydroxide solution while stirring in an ice bath to make the neutralization degree of the acrylic acid 60-80%, and then the acrylamide, 2-acrylamide-2-methylpropanesulfonic acid and crosslinking agent are added and stirred to dissolve to obtain a mixture; the initiator is added to deionized water to dissolve to obtain an initiator solution; the transparent viscous substance is poured into the gelatinized starch and stirred evenly, then the mixture is added, and nitrogen gas is introduced to remove air, then the initiator solution is added, stirred evenly, the cup is sealed with plastic wrap, placed in a 60°C water bath, heated to 65-75°C, magnetically stirred for 10 minutes, then stirring is stopped, and then the reaction is kept at 65-75°C for 4-5 hours to obtain a translucent gel-like substance, which is the starch-based hydrogel.

[0056] After obtaining the starch-based hydrogel, the present invention sequentially freeze-dries and calcines the starch-based hydrogel to obtain the starch-carbon aerogel adsorbent.

[0057] In this invention, the freeze-drying temperature is preferably -30 to -40°C, and the time is preferably until the solvent is completely removed.

[0058] In this invention, it is preferable to break down and wash the starch-based hydrogel before freeze-drying.

[0059] The present invention preferably uses a grinder to grind the starch-based hydrogel.

[0060] In this invention, the detergent used for washing is preferably water, the washing is preferably performed twice, and after washing is completed, the detergent is preferably filtered out using a filter screen.

[0061] In this invention, the freeze-drying is preferably carried out in a freeze dryer.

[0062] After the freeze-drying is completed, the present invention preferably performs vacuum drying to obtain a white flocculent substance, and then performs the calcination.

[0063] In this invention, the vacuum drying temperature is preferably -30 to -40°C, and the drying time is preferably until the solvent is completely removed.

[0064] In this invention, the calcination temperature is preferably 700-900℃, more preferably 800-900℃, the holding time is preferably 2-3h, and the heating rate from room temperature to the calcination temperature is preferably 2-5℃ / min, more preferably 3-4℃ / min.

[0065] In this invention, the calcination is preferably carried out under nitrogen protection.

[0066] In this invention, the calcination is preferably carried out in a tubular furnace.

[0067] After the calcination is completed, the present invention preferably cools the obtained calcined product to room temperature naturally, soaks it in deionized water to remove salt (including sodium carbonate), and then dries it to obtain the starch carbon aerogel adsorbent.

[0068] In this invention, the soaking time is preferably 24 hours, and the temperature is preferably room temperature.

[0069] In this invention, the drying is preferably oven drying, the oven drying temperature is preferably 100°C, and the drying time is preferably until the moisture is completely removed.

[0070] The present invention also provides a starch-carbon aerogel adsorbent prepared by the preparation method described in the above technical solution.

[0071] This invention also provides the application of the starch-carbon aerogel adsorbent described in the above technical solution in the field of organic dye adsorption.

[0072] In this invention, the organic dye is preferably methylene blue (MB).

[0073] In this invention, the application preferably includes the following steps: adding the starch-carbon aerogel adsorbent to a solution containing MB for adsorption.

[0074] In this invention, the concentration of MB in the solution is preferably 100 mg / L, and the dosage of the starch-carbon aerogel adsorbent is preferably 200 mg / L.

[0075] In this invention, the adsorption temperature is preferably 25°C, and the adsorption time is preferably 6 to 24 hours.

[0076] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0077] Example 1

[0078] (1) Preparation of starch-based hydrogel: Take four 100mL beakers. In beaker #1, add 1.0g of corn starch and 15mL of deionized water, stir well, and then place in a 90℃ water bath for gelatinization for 15min. Remove and cool to room temperature for later use. In beaker #2, add 0.5g of sodium carboxymethyl cellulose (CMC) and 30mL of deionized water, and stir until the powder is completely dissolved to obtain a transparent viscous substance. In beaker #3, add 5mL of acrylic acid (AA), and while stirring in an ice bath, add sodium hydroxide solution (15wt%) dropwise to neutralize the AA to 60%. Then add 3.0g of acrylamide (AM), 2.0g of 2-acrylamido-2-methylpropanesulfonic acid (AMPS), and 0.2g of crosslinking agent N,N-methylenebisacrylamide (NMBA), and stir to dissolve. In beaker #4, add 0.06g of initiator ammonium persulfate (APS) and then add 5mL of deionized water to dissolve. Pour solution #2 into beaker #1 and stir well. Then pour solution #3 into beaker #1 and stir well. Simultaneously, purge nitrogen gas into beaker #1. After the air in the beaker is expelled, pour solution #4 into beaker #1, stir well, seal the mouth of the beaker with plastic wrap, and place it in a 60℃ water bath. Raise the temperature to 75℃ (heating rate 2.5℃ / min), and stir magnetically for 10 minutes, then stop stirring. Then maintain the reaction temperature at 75℃ for 4 hours to obtain a translucent gel.

[0079] (2) Freeze-drying of starch-based hydrogel: The block hydrogel was crushed using a grinder and soaked twice with 1L of deionized water. Excess water was filtered off with a filter screen. The water-absorbed gel particles were placed in a freeze dryer at -30℃, first fully frozen, and then vacuum dried at -30℃ to obtain white flocculent material.

[0080] (3) Preparation of starch-carbon aerogel adsorbent: The freeze-dried white flocculent was placed in a crucible and calcined at high temperature in a tube furnace under nitrogen protection. The heating rate was 3℃ / min, the calcination temperature was 800℃, and the temperature was maintained at 800℃ for 2 hours. After natural cooling to room temperature, the starch-carbon aerogel adsorbent was obtained.

[0081] (4) Washing of starch-carbon aerogel adsorbent: The prepared starch-carbon aerogel adsorbent was placed in sufficient deionized water and soaked for 24 hours to remove salt. The filtered powder was dried in an oven at 100°C and then used for adsorption experiments.

[0082] The specific surface area of ​​the starch-carbon aerogel adsorbent was determined using a specific surface area analyzer, and its specific surface area was 1508 m². 2 / g. When using starch-carbon aerogel adsorbent to adsorb methylene blue (MB) in aqueous solution, with a MB concentration of 100 mg / L, no pH adjustment, a dosage of 200 mg / L, an adsorption temperature of 25℃, and an adsorption time of 24 h, the equilibrium adsorption capacity was 497.32 mg / g, and the removal rate was 98.5%.

[0083] Figure 1 The image shows the infrared spectrum of the starch-based hydrogel in Example 1. Figure 2 The infrared spectrum of the starch-carbon aerogel adsorbent in Example 1 shows that, in the infrared spectrum of the starch-based hydrogel, at 3330 cm⁻¹... -1 and 3200cm -1 A double peak for primary amides appeared at 1657 cm⁻¹. -1 The peak at 1552 cm⁻¹ represents the vibrational absorption peak of the carbonyl group. -1 The peaks at 1447 and 1402 cm⁻¹ represent the bending vibration peaks of NH. -1 -COO - Symmetrical and asymmetric stretching vibration peaks; 1187 cm⁻¹ -1 and 1040cm -1 The characteristic absorption peak at 3739 cm⁻¹ is for sulfonic acid groups. The appearance of these new peaks indicates the presence of carbonyl, amino, carboxyl, and sulfonic acid groups in the hydrogel structure, confirming the successful synthesis of the target product. In the infrared spectrum of the starch-carbon aerogel, 3739 cm⁻¹ is a characteristic absorption peak for sulfonic acid groups. -1 The absorption peak at 3426 cm⁻¹ represents the free hydroxyl group. -1 The absorption peak at 1625 cm⁻¹ represents the associated hydroxyl group. -1 The absorption peak at 1024 cm⁻¹ is the C=O peak. -1 The sharp peak at 800–630 cm⁻¹ is the absorption peak of CO. -1 The broad peak between 562 cm⁻¹ is formed by the superposition of absorption peaks from CC and CN. -1 The shoulder peaks at that location are absorption peaks of CS. The appearance of these peaks indicates that the carbon aerogel contains N and S elements and active groups, which can adsorb dyes.

[0084] Figure 3 Here is an electron microscope image of starch from Example 1. Figure 4 This is an electron microscope image of sodium carboxymethyl cellulose from Example 1. Figure 5 This is an electron microscope image of the starch-based hydrogel in Example 1. Figure 6 The electron microscope image of the starch-carbon aerogel adsorbent in Example 1 shows that the particle shape of starch and sodium carboxymethyl cellulose completely disappears in the starch-based hydrogel, and honeycomb-like pores appear in the block hydrogel. The diameter of the pores is relatively large, above 10 μm. After calcination, the skeletal structure of the gel is preserved, and more pores appear. The diameter of the pores becomes smaller, mostly below 1 μm.

[0085] Figure 7 This is a photograph of the starch-based hydrogel in Example 1. Figure 8 This is a photograph of the starch-based hydrogel after it has absorbed water, as shown in Example 1. Figure 9 This is a photograph of the starch-based hydrogel after freeze-drying in Example 1. Figure 10 The image shown is a physical representation of the starch-based carbon aerogel adsorbent in Example 1. It can be seen that the starch-based hydrogel is a milky white gel-like substance that can absorb water but does not dissolve itself. After freeze-drying, the starch-based hydrogel yields a white, fluffy, flocculent substance with minimal volume change. After calcination, the dried gel yields a black, fluffy, sheet-like starch-based carbon aerogel.

[0086] Example 2

[0087] Same as Example 1, except that the amount of AMPS used in the preparation process was 1.0g, the heating rate during calcination was 5℃ / min, and the calcination temperature was 800℃.

[0088] The specific surface area of ​​the starch-carbon aerogel adsorbent was determined using a specific surface area analyzer, and its specific surface area was 1435 m². 2 / g. Using this starch-carbon aerogel adsorbent to adsorb methylene blue (MB) in aqueous solution, when the concentration of MB in the solution was 100 mg / L, the pH value was not adjusted, the dosage was 200 mg / L, the adsorption temperature was 25℃, and the adsorption time was 24 h, the equilibrium adsorption capacity was 489.30 mg / g, and the removal rate was 98.4%.

[0089] Example 3

[0090] Same as Example 1, except that the amount of AMPS used in the preparation process was 0.5g, the heating rate during calcination was 4℃ / min, and the calcination temperature was 800℃.

[0091] The specific surface area of ​​the starch-carbon aerogel adsorbent was determined using a specific surface area analyzer, and its specific surface area was 763 m². 2 / g. When using starch-carbon aerogel adsorbent to adsorb methylene blue (MB) in aqueous solution, with a concentration of MB of 100 mg / L, no pH adjustment, a dosage of 200 mg / L, an adsorption temperature of 25℃, and an adsorption time of 24 h, the equilibrium adsorption capacity was 429.40 mg / g, and the removal rate was 85.9%.

[0092] Example 4

[0093] Same as Example 1, except that the amount of AMPS used in the preparation process was 2.0g, the heating rate during calcination was 3℃ / min, and the calcination temperature was 700℃.

[0094] The specific surface area of ​​the starch-carbon aerogel adsorbent was determined using a specific surface area analyzer, and its specific surface area was 678 m². 2 / g. Using this carbon aerogel to adsorb methylene blue (MB) in aqueous solution, when the concentration of MB in the solution was 100 mg / L, the pH value was not adjusted, the dosage was 200 mg / L, the adsorption temperature was 25℃, and the adsorption time was 24 h, the equilibrium adsorption capacity was 238.75 mg / g, and the removal rate was 47.8%.

[0095] Example 5

[0096] Same as Example 1, except that the amount of AMPS used in the preparation process was 2.0g, the heating rate during calcination was 4℃ / min, and the calcination temperature was 900℃.

[0097] The specific surface area of ​​the starch-carbon aerogel adsorbent was determined using a specific surface area analyzer, and its specific surface area was 1305 m². 2 / g. When using starch-carbon aerogel adsorbent to adsorb methylene blue (MB) in aqueous solution, with a MB concentration of 100 mg / L, no pH adjustment, a dosage of 200 mg / L, an adsorption temperature of 25℃, and an adsorption time of 24 h, the equilibrium adsorption capacity was 488.00 mg / g, and the removal rate was 97.6%.

[0098] Example 6

[0099] Same as Example 1, except that the amount of CMC used in the preparation process is 1.0g, the CMC is dissolved in 50mL of water, the amount of AMPS is 2.0g, the heating rate during calcination is 3℃ / min, and the calcination temperature is 800℃.

[0100] The specific surface area of ​​the starch-carbon aerogel adsorbent was determined using a specific surface area analyzer, and its specific surface area was 1348 m². 2 / g. When using starch-carbon aerogel adsorbent to adsorb methylene blue (MB) in aqueous solution, with a concentration of MB of 100 mg / L, no pH adjustment, a dosage of 200 mg / L, an adsorption temperature of 25℃, and an adsorption time of 24 h, the equilibrium adsorption capacity was 488.50 mg / g, and the removal rate was 97.7%.

[0101] Comparative Example 1

[0102] Same as Example 1, except that the amount of AMPS used in the preparation process was 0g, the heating rate during calcination was 3℃ / min, and the calcination temperature was 800℃.

[0103] The specific surface area of ​​the starch-carbon aerogel adsorbent was determined using a specific surface area analyzer, and its specific surface area was 252 m². 2 / g. When using starch-carbon aerogel adsorbent to adsorb methylene blue (MB) in aqueous solution, with a concentration of MB of 100 mg / L, no pH adjustment, a dosage of 200 mg / L, an adsorption temperature of 25℃, and an adsorption time of 24 h, the equilibrium adsorption capacity was 61.40 mg / g, and the removal rate was 12.3%.

[0104] Comparative Example 2

[0105] Same as Example 1, except that the amount of AMPS used in the preparation process was 2.0g, the heating rate during calcination was 3℃ / min, and the calcination temperature was 600℃.

[0106] The specific surface area of ​​the starch-carbon aerogel adsorbent was determined using a specific surface area analyzer, and its specific surface area was 125 m². 2 / g. When using starch-carbon aerogel adsorbent to adsorb methylene blue (MB) in aqueous solution, with a concentration of MB of 100 mg / L, no pH adjustment, a dosage of 200 mg / L, an adsorption temperature of 25℃, and an adsorption time of 24 h, the equilibrium adsorption capacity was 27.40 mg / g, and the removal rate was 5.4%.

[0107] Comparative Example 3

[0108] Same as Example 1, except that the amount of AMPS used in the preparation process was 2.0g, the heating rate during calcination was 1℃ / min, and the calcination temperature was 800℃.

[0109] The hydrogel was completely burned, and no carbon aerogel was formed.

[0110] Comparative Example 4

[0111] Same as Example 1, except that the amount of CMC used in the preparation process is 0g, the amount of AMPS is 2.0g, the heating rate during calcination is 3℃ / min, and the calcination temperature is 800℃.

[0112] The specific surface area of ​​the starch-carbon aerogel adsorbent was determined using a specific surface area analyzer, and its specific surface area was 1.5 m². 2 / g. When using starch-carbon aerogel adsorbent to adsorb methylene blue (MB) in aqueous solution, with a concentration of MB of 100 mg / L, no pH adjustment, a dosage of 200 mg / L, an adsorption temperature of 25℃, and an adsorption time of 24 h, the equilibrium adsorption capacity was 0 mg / g, and the removal rate was 0%.

[0113] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method of making a starch carbon aerogel adsorbent, characterized by, The method comprises the following steps: mixing starch with water to gelatinize the starch and obtain gelatinized starch; mixing the gelatinized starch, sodium carboxymethyl cellulose, grafting monomers, initiator and crosslinking agent to perform grafting and crosslinking reaction and obtain starch-based hydrogel; the grafting monomers include acrylamide, acrylic acid and 2-acrylamide-2-methylpropanesulfonic acid, and the crosslinking agent includes N,N-methylenebisacrylamide; performing freeze-drying and calcination on the starch-based hydrogel in sequence to obtain the starch carbon aerogel adsorbent; the mass ratio of the sodium carboxymethyl cellulose to 2-acrylamide-2-methylpropanesulfonic acid is 0.5-1:0.5-2.

2. The production method according to claim 1, characterized by, the mass ratio of the starch to sodium carboxymethyl cellulose is 1-2:0.5-1.

3. The preparation method according to claim 1, characterized in that, the amount ratio of the acrylamide, acrylic acid and 2-acrylamide-2-methylpropanesulfonic acid is 2-3g:0-5mL:0.5-2g, and the amount of the acrylic acid is not 0.

4. The production method according to claim 1, characterized by, the grafting and crosslinking reaction comprises the following steps: after being warmed from 60℃ to 65-75℃, keeping the temperature for 4-5h.

5. The preparation method according to claim 4, characterized in that, the warming rate of the warming is 2.5℃ / min.

6. The method of claim 1, wherein, the temperature of the freeze-drying is -30--40℃.

7. The production method according to claim 1 or 6, characterized by, the temperature of the calcination is 700-900℃, the keeping time is 2-3h, and the warming rate from room temperature to the temperature of the calcination is 2-5℃ / min.

8. The starch carbon aerogel adsorbent prepared by the preparation method in any one of claims 1-7.

9. The application of the starch carbon aerogel adsorbent in claim 8 in the field of organic dye adsorption.

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